Radiographic timing apparatus



July 7, 1931 w. s. WERNER RADIOGRAPHIC TIMING APPARATUS Filed July 12, 1927 3 Sheets-Sheet 1 v lllllllllll 'IIIIII [51 van for,

July 7, 1931. w. s. WERNER RADIOGRAPHIC TIMING APPARATUS Filed July ".2, 1927 '3 Sheets-Sheet 2 "II -In! II IHI Hill I llllll llllmlllllfllfim IEfillll IIIIII MINIHIIII- lml "mu ill IHIIII S INVENTOR. W M,

A TTORNEY.

July 7, 1931. w. s. WERNER RADIOGRAPHIC TIMING APPARATUS 3 Sheets-Sheet 5 Filed July 12, 1927 1 N VEN TOR. I WUQ/WM/I mewg ATTORNEY.

Patented July 7, 1931 UNETED STATES PATENT OFFICE WILBU'P. S. WERNER, OF COVINGTON, KENTUCKY, ASSIGNOR TO THE KELLEY-KOETT MANUFACTURING COMPANY, OF COVINGTON, KENTUCKY, A CORPORATION OF OHIO RADIOGRAPHIC TIMING APPARATUS Application filed July 12,

My invention relates to improvements in circuit closing apparatus adapted for use as a radiographic exposure meter. One of its objects to provide apparatus adapted to 1 regulate with accuracy and reliabilty the periods during which an electrical apparatus, an X-ray generator for instance, is energized. Another object is to provide apparatus adapted to open and close an alternating current circuit synchronously. Another object is to provide improved apparatus adapted to successively close and open an alternating electrical circuit with relatively short time intervals between the closing and opening of the circuit. Another object is to provide improved apparatus to open and close an alternating electrical circuit synchronously with relatively short time periods between the closing and opening of the circuit. Another object is to provide improved apparatus adapted to close an alternating electrical circuit through the X-ray generator of a radiographic apparatus synchronously for a predetermined number of impulses, alternations, or cycles, of the energizing circuit, whereby practically instantaneous and apparently motionless radiographs of moving organs of the body may be obtained. Another object is to provide an improved apparatus adapted to reliably and accurately make radiographic exposures of predetermined length in synchronism with the energizing circuit. Another object is to provide an improved apparatus for synchronously closing and opening an alternating current circuit so that the make and break of the switch contacts occur when the current is substantially at zero potential. My invention also comprises certain details of form and arrangement, and combination of components, all of which will be fully set forth in the description oi: the accompanying drawings, in which:

Fig. 1 is a diagramatic illustration of a circuit closing and opening apparatus embodyin my improvements.

Fig. 2 is a plan of the switch controlling cams detached.

Fig. 3 is a side elevation of the same.

a is a detail illustrating a modification 1927. Serial No. 205,269.

of a portion of the switch mechanism shown in Fig. 1.

The accompanying drawings show one embodiment of my invention in which 15 represents an alternating electrical circuit, for instance the energizing circuit by means of which the primary 16 of a step-up transformer is energized to provide in its secondary 17 a high tension alternating current, which after being rectified at 20 is employed to excite an X-ray generator member 18 for a predetermined time period suflicient to make a radiographic exposure upon a sensitive plate 19. A two way double pole switch 21 is preferably employed to positively cut in or close the circuit 15 at the switch poles 22 and 23, or when thrown in the opposite direction, to open the circuit 15 at the mvitch poles 22 and 23, and to close a multiple branch circuit through the switch poles 24 and 25. This multiple branch circuit includes automatical ly actuated and synchronously and mechanically actuated mechanism, whereby the circuit 15 may be closed for predetermined periods of time, to thereby energize the primary 16 and secondary 17 of a step-up transformer and thereby provide a high tension current flow through the X-ray generator 18, and thereby generate or excite. for relatively short and predetermined periods of time, trains of X-rays which pass from the X-ray generator 18 through an. object 29 to be radiographed and thence to a sensitized plate 19 encased in a suitable cassette or plate holder 31. The current flowing through the transformer secondary 17 and X-ray generator 18 is designed to be rectified by known means which has not been specifically illustrated. The circuit 15 may be of the usual or standard sixty cycle type, or Where radiographic exposures of unusually short duration are desired, for instance exposures of less than one-one hundred and twentieth of a second, the circuit 15 may be increased to one hundred and twenty cycles or more if desired, and of one hundred and ten volts or a higher voltage.

The circuit 15 to be synchronously inter rupted may be and generally is of relatively large amperage, for instance one hundred and fifty or more amperes, an to open a air cuit of such amperage at maximum voltage would result in considerable arca-ge, in injury to the switch mechanism and to other undesirable results. The auxiliary branched circuit, or controlling circuit, is of relatively small amperage, for instance one to three amperes, and the closing and opening thereof at the various switches, 43, 45, 59, 94 and 98 will cause relatively small arcing, and small injury to the mechanism and the opening and closing of said auxiliary circuit need not of necessity be synchronous.

The multiple branch circuit above referred to is preferably supplied at the terminals 24 and 49 with electricity from the usual service line 32, for instance with sixty cycle current at one hundred and ten or two hundred and twenty volts. 7 tiple branch circuit leads through the switch poles 24 and 25't-o one pole 34 of a switch 43, theswitch lever 35 of which is normally held in open position by means of a spring 36. A section or loop of the circuit branch 33 leads from the switch terminal 34 to one terminal 37 of a push-button switch, or similar switch 38 adapted to be manually closed by the operator to thereby initiate a cycle of operations resulting in a periodic closing and opening of circuit 15, the development of a train of X-rays and exposure of the sensitive plate thereto. The opposite terminal 39 of theswitch 38 is connected by a section of the circuit 33, with. the opposite terminal 40 of the switch 43. From the switch terminal 40 the circuit branch 33 passes through thecoil 41 of a solenoid, the armature 42 of which is operatively connected to the switch lever 35, so as to oppose the spring 36 and close theswitch 43' when the coil 41 is energized by a current flowing therein, which serves to short circuit the current through the switch arm 35 from the switch terminal 34 directly to the switch terminal 40, thereby practically temporarily excluding the switch 38 from the circuit and conducting the current through the switch arm 35 past the switch 38; The circuit branch33 continues from the coil 41 to the switch terminal 44 of aswitch 45, the switch arm 46 of which is normally closed by a spring 47, thereby completing the circuit branch 33 to the switch terminal 48, from whence the circuit branch 33 continues to the opposite terminal 49 of the service line 32. v

A circuit branch 50 leads from the terminals 24 and 25 to an alternating current motor .51 which rotates in phase or in synchronism with the alternating current'supplied to said motor. A train of gears 52, 53, 54 and 55 serve to drive ashaft 56 in synchronism' with the current supplied to the motor 51, but at a relatively slower rate of rotation than that of the motor 51, for instance the motor 51 may rotate at substantially eighteen hundred revolutions per minute, while the One branch 33 of said mul shaft 56 rotates at a definite ratio to that of the motor and at substantially one hundred and twenty revolutions per minute, or one revolution to each thirty cycles of a sixty cycle current, and is in definite relation to or in synchronism with the current supplied to the motor. The circuit branch 50 continues from the motor to the terminal 49 of the service circuit 32. The shaft 56 has mounted thereon to rotate therewith a circuit closing and circuit breaking cam or disk 57. The shaft 56 also carries thereon and rotatable therewith another. circuit closing and circuit breaking cam or disk 58.

Mounted adjacent to the cam 57 is a switch 59 provided with a switch arm 60 which is normally held open by means of a spring 61. A shaft 62 is mounted in hearings to move endwise, and is attached by a pin 63 to the switch arm 60, so as to actuate said switch arm, or to be actuated by said switch arm and spring 61. The opposite end 131, of the shaft 62 projects into the path of an inclined or beveled section 164 carried by the cam disk 57, so that at each revolution of the shaft 56 the cam face 64 will engage the end of the shaft 62 and move said shaft 62 and switch arm 60 in the direction to close the switch 59, while the spring 61 serves after each engagement of the cam face 64 with the end of shaft 62, to return the shaft 62 and switch arm 60 to their open or normal position. 7

A solenoid casing or housing 65 is adjustably mounted to move in a vertical plane, or if desired in a horizontal plane, guides being adjustable transversely of the shaft 56, and radially relative to the cam 58 by means of a feed screw or micrometer screw66, adapted to be operated by a hand crank 67, and provided with a pointer 68 movable over a scale 69t-o indicate thereon the position of the casing 65 and parts carried thereby relative to the cam 58. The casing 65 is provided with two guide rods 70 rigid relative to the casing 65 and serving as guides for a switch 71 which is'adjustable to and from the cam 58. The switch 71 is movable along the guide rods 7 0 by means of an armature shaft 72, which is movable endwise relative to the casing 65 by means of a coil 73 carried by said casing 65. The switch 71 is provided with a switch arm 74 which is normally held'in open position by means of a spring 7 5. A shaft 76 is attached by a pin 77 to the switch arm 74, and when in position to be engaged by the inclined face 178 carried by the cam 58, is adapted to be moved thereby endwise, and to move the switch arm 74 to closed position against the action of the spring 75. The solenoid shaft 72 when energized by current flowing in the coil 73, moves the switch 71 and shaft 76 along the guide rods 70 into position for the end. of the shaft 76 to be engaged by cam faces17 8 and 78 of the cam 58. The terminals 79 and 80 of the switch 71 are included in the circuit 15, so that move ment of the switch arm 74 serves to open and close the circuit 15. The rear end of the armature shaft 72 is provided with a notch or detent 81 adapted to be engaged by a bolt or latch lever 82 to lock the shaft 72 in position for the shaft 76 to be engaged by the faces 178 and 78 of the cam disk 58. A spring 83 serves to retract the shaft 72 as soon as released by the latch lever 82.

The latch lever 82' is mounted upon a pivot pin 84, and is normally held in position to engage the detent 81 by means of a spring 85.

- A solenoid casing 86 mounted stationarily relative to the solenoid casing 65 and adjustable therewith by means of the feed screw 66 is provided with an energizing coil 87 and a magnetic core 88, adapted to be actuated when said coil 87 is energized. The lower end of the core 88 is pivotally attached to the latch bar 82, and serves to lift said latch bar out of the detent 81 at an appropriate period in the cycle of operation. At the same time that the core 88 lifts the latch bar 82, its upper end contacts with a dovniwardly directed stud 89 which is pivotally attached to the switch lever 46, and serves to lift said switch lever and break the electrical contact in circuit branch 33 across from the terminal 44 to terminal 48.

A switch board or slide 90 is provided with ways mounted to slide in guides 91 in a direction transversely to the plane in which the cam 57 rotates. Mounted upon the switch board 90 is a solenoid casing 150, see Fig. 4, but not shown, in Fig. 1 having an energizing coil 92 and a core or armature 93 adapted tobe actuated endwise thereof when the coil 92 is energized. A switch 94 having a normally open switch lever 95 held normally open. by a spring 96 and connecte'c by a pin 97 to the stem of the solenoid core 93 is adapted to be opened and closed at appropriate intervals in the cycle of operations. A switch 98 having a normally closed switch lever 99 is connected to the stem of the solenoid 93 by a pin 100, so that when the switch 98 is open the switch 9-4 is closed. At one end of the solenoid 93 is a stud 101 which is adapted to project into the path of the cam faces 164i and 6 1 to thereby mechanically shift the core 93 endwise whenever the switch board 90 is shifccd toward the right hand'in Fig. 1 to bring the end 101 into engagen'ient with the cam disk 57. The spring 96 will shift the core 93 in the reverse direction after each ongagement of the member 101 with the cam 64. The switch board 90 is attached-through a pivoted link 102 to a lever 103, which lever is stationarily pivoted upon a pin 10%. The free end of the lever 103 is pivoted to one end of a link or connecting rod 105. The opposite end of the connecting rod 105 is pivotally connected to the free end of'a lever 106.

The lever 106 is pivotally mounted upon a pin 107, stationarily relative to the solenoid housing 65, so as to be moved therewith by the feed screw 66. The opposite end of the lever 106 is connected by means of a pin 108 to the stem of the solenoid 72, so that when the solenoid 72 in Fig. 1 is moved toward the left hand the lever 106 is rocked upon the pin 107, the connecting rod 105 moves endwise toward the right hand, and the switch board 90 is drawn by the lever 103 and link 102 toward the right hand until the member 101 is in position to be engaged by the rotating cam 64.

A branch 109 of the circuit 32 divides from the circuit branch 33 at the switch terminal 10, and leads thence to the terminal 110 of coils 87 of the solenoid 88, and from the opposite terminal 112 of coil 87 to the terminal 11 1 of the switch 94, thence through the switch lever 95 to the terminal 115 of the switch 94, thence to the terminal 116 of switch 98 and thence by way of branch 33 to the terminal l9 of circuit 32.

A branch 117 of the circuit 32 divides from the branch 33 at the switch terminal 40, and leads thence through the coil 92 of the solenoid 93 and thence to the terminal 114 of the witch 9st, from which point it unites with the branch 109 until the terminal 49 of circuit 32 is reached.

A branch 118 of circuit 32 divides from the branch 33 at the switch terminal 40 and leads thence to the terminal 119 of the coil 73, and from the opposite terminal 120 of the coil 73 to the terminal 122 of the switch 59, thence through the switch arm 60 to the terminal 123 of the switch 59, thence to the terminal 124 of the switch 98, thence by the switch lever 99 to the switch terminal 116 of switch 98, and thence by uniting with branch 109 and branch 33 to the terminal, 49 of circuit 32.

One important advantage attained by my improved apparatus is to provide for invariably closing and opening the circuits par ticularly circuit 15 when they are in a substantially neutral condition, with practically no current flow, thereby providing for opening and closing the various switches with practically no arcing and practically no corl rosion or injury to the terminals at points where the circuit branches are opened or closed. Another advantage to be able to usefully employ the current covering one sii igle impulse or half cycle thereof, or one complete cycle thereof, or any desired number of successive impulses or cycles t icreof. Another advantage is to be able to usefully em ploy the current covering a single impulse or half cycle, or a plurality of successive impulses or cycles for the generation of trains of X-rays, and to thereby reliably measure the extent to which a sensitive plate is exposed to the influence of X-rays, and thereby be able to give moving objects a maximum ezrposurc in the short period available to X-rays without liability to show movement of the object and thereby destroy the sharpness and accuracy of the image.

In operation for the exposure of sensitive plates to trains of i-rays passing through moving or stationary objects, the control cabinet shown in Fig. 1 provides for the regulation of the current through the primary as to voltage and current to thereby develop a voltage and current through the X-ray generator suited to the nature of the work in hand, or object to be radiographed. If a longer timed exposure is desired the switch 21 may be employed to close the circuit 15 across the terminals 22 and 3. If a short timed exposure is desired the switch 21 is employed to close the circuit 32 across the terminals '24 and 25, leaving one gap in the circuit 15 at theterminals 22 and 23, and another parallel gap in circuit 15 where the switch arm 74 is held open by the spring 7 5.

Closing the auxiliary circuit at the terlninals 24 and 25 serves to close the circuit through the branch starting the synchronous motor 51 and the shaft 56 and cams 57 and 58 to rotate in synchronism with the current in circuit 32, and leaving branches 33, 109, 117, and 118 open at the push-button switch 38, and also at the switch 13. It is possible for the push button switch to be variously actuated, for instance it may be closed for a very short interval of time and released, it may be closed and held closed for a relatively long period of time, or for a relatively' short period of time, and it may be repeatedly closed with short open intervals between. Whatevercharacter of manipulation the switch 38 may receive from the operator, it is desired that but one predetermined cycle of operations result therefrom in producing the radiographic exposure.

Therefore manual closure of the switch 38 serves to close the circuit branch 33, and energize the coil 11, which closes the switch arm 35 of switch 13 to thereby cut the switch 38 out of the circuit 33 and render its operation ineffectual until after the cycle of operation has been completed and the exposure has been completed. The branch 118 is periodically closed at switch 59 by the shaft 62 and cam face 64 over a period corresponding to the active period of cam 58 and the inactive period of the cam faces 78. This is a due to the speed ratio of the shaft 56 and the fraction thereof covered by the active face 64 of cam disk 57 being so proportioned as to close the switch for only a small fraction of each revolution of the shaft 56 and cam disk 1 57, leaving the switch 59 open the major portoward the shaft 56, thereby providing for adjusting thestem 76 radially of the face of the cam 58 to bring the stem 76 opposite relatively short or relatively long cam faces or sections 7 8, to thereby close the switch 71 selectively for relatively short and longer periods, depending upon the length of radiographic exposure desired. "The closing of the circuit branch 118 also energizes the coil 73 and causes the core 72 to shift endwise toward. the cam 58 until the stem 76 is in the path of travel of the cam faces 178 and 78, which causes the stem 76 to close the switch arm 74 and hold it closed for a greater or less predetermined period, thereby closing the circuit 1.5 across the contacts 79 and 80 and supplying high tension current for the prescribed period of time through the X-ray generator 18 and causing trains of X-rays to stream therefrom through the object 29 to the sensitive plate 19, also for the prescribed period of time. i

The cam faces 78 are cut so that their degrees of length be'ara definite relation to the frequency of the alternating current, each face representing a definite number of-im-' pulses or cycles. By phasing or adjusting the cam 58 on the shaft 56 clockwise or anti-clockwise, the synchronously operated cam faces 78 are made to strike the pin 76 which closes the lever 7 4 of switch 71 when the alternating current is at zero potential, and in so much as the lengths of the cam faces represent a definite number of cycles, the pin 76 is released operating the'switch 71 at a predetermined time or period when the alternating currentis again at zero potential. On account of the synchronous action of switch 71,

heavy currents can be made and broken 7 without any arcing at the switch contacts, or injury thereto.

. When the core 72 moves toward the cam 58 the detent 81 moves under the free end of the latch bar 82, allowing the latch bar to engage the detent 81 and latch the core 72 in position for the cam 58 to engage the stem 76, even though the circuit branch 118 be opened and the coil 73 deenergized. Thus even though the period during which the switch 59 is closed should be shorter than the prescribed period of radiographic exposure, the core 72 will hold the switch 71 in position to be closed by the cam face 78 until the cam 58 has completed its action upon the stem 76 and it is desired to release the core 7 2 from the latch bar 82. This is effected through the circuit branch 117, and an adjustment of the switch board 90 toward the cam 57. When the core 72 moves toward the cam 58, the switch board 90 is moved by the levers 103 and 106, and connecting rod 105 toward the cam 57 The cam faces 78 are set upon the shaft 56 sufficiently in advance of the cam face 64, so that any one of the cam faces 78 has reached the limit of its action before the cam face 64 reaches and acts upon the stud 101 to thereby clo th ,1 e

switch 94 and at the same time open the switch 98. Closing the switch 94 serves to close the circuit branches 109 and 117, and opening the switch 98 serves to open the circuit branch 118. Closing of the branch 109 energizes the coil 87, causing the armature 88 to lift the latch from detent 81, while at the same time opening of branch 118 deenergizes the coil 73, allowing spring 83 to retract the core 72 and with it the switch 71 and stem 76 out of the path of the cam disk 58. l/Vhen the circuit 109 is closed the armature 88 also contacts with the stud 89 and opens the switch 46 thereby opening the branch 33, which deenergizes the coil 41 and permits the spring 36 to open the switch 43. Closing of the branch 117 energizes the coil 92, thereby holding the armature 93 in position to hold the switch 94in closed position and switch 98 in open position, until the cycle of operations is completed and the operator is ready to release the switch 38 at the terminals 37 and 39 to thereby open all the circuit branches except 50 of the motor. Movement of the armature 7 2 toward the right hand reacts through the levers 103 and 106 upon the switch board '90 to move the switch board toward the left hand and the stem 1.01 out of the path of the cam disk 57.

In the event that the operator initiates a cycle of operation by closure of the branch 33 for a very short period of time at the switch 38, the switch 43 is thereby automatically closed soas to insure procedure and completion of the cycle. of operations even though the switch 38 may be opened by the operator before the cycle of operations is completed. In the event that the operator closes the switch 38 repeatedly during the progress of a cycle of operations, the automatic closing of the switch 43 will render any closing of switch 38 subsequent to the first closure thereof during a single cycle of operations ineffectual to change or interfere with the 5 regular completion of said cycle of operation,

and will prevent the initiation of a second cycle of operations before the first cycle of operations has been completed. In the event that the operator closes the switch 38 and holds it closed during and after the completion of the cycle of operations the closed circuits 117 and 109 together with movement of the stems 76 and 101 out of the paths of the cams 57 and 58 will prevent initiation of a second cycle of operations. As soon as the circuit branches 109 and 117 are closed, the auxiliary branch 33 will be opened at the switch 45 due to the action of the armature 88 upon the stud 89. With the switch 45 opened switch 43 opens automatically and the circuits 109 and 117 remain effective only if and as long as switch 38 is manually held closed. Circuit 109 energizes coil 87 to ac tuate armature 88 and lift the latch 82 from the detent 81, allowing the core 7 2 to move toward the right hand in Fig. 1, thereby moving the slide 90 toward the left hand in Fig. 1. The stems 76 and 101 are thereby shifted out of the paths of the cams 57 and 58, and will thus prevent the initiation of a second cycle of operation until after the circuit 117 has been opened at the switch 38. T he circuit 117 energizes coil 92 closing the switch 94 and opening the switch 98, thereby opening the circuit 118 preventing reenergizing of the winding 73 of magnet until after manual release of the push-button switch As illustrated in Figs. 2 and 3 the cam disk 57 has an inclined face 164 up which the stem 131 of the shaft 62 rides to close the switch 59, and a plane face 64 which predetermines the period of time, or fraction of revolution of shaft 56, during which the switch 59 remains closed during each revolution of the shaft 56. The cam 57 has a series of slots 33, and the cam disk 58 has a series of bolt holes 134 through which boits 130 are adapted to be passed to clamp the cam disks 57 and 58 together, and to adjust one of said cam disks relative to the other until they serve to make and break the circuit 15 at periods of practically no current flow. The cam disk 58 has a relatively wide inclined face 178 to be engaged by the stem 76 to close the switch 71. The edge of the cam disk 58 is cut into a series of steps or notches 136 to thereby provide a plane face 78 divided into a series of concentric cam faces 78 of relatively different lengths, which predetermine the length of time or fraction of a revolution of the cam disk 58, during which the stem 76 will ride upon the plane face 78 of the cam disk 58 to hold the switch 71 closed. The stem 76 is adjustable by means of the feed screw 66 to different positions radially of the cam disk 58 to bring the stem 7 6 opposite a long or short section of the plane face of the cam, depending upon the length of exposure desired.

In Fig. 1 I have shown the several switches 43, 45, 59, 71, 94 and 98 of conventional knife blade design and such switches are adapted to carry out my invention. I have also found switch mechanism such as shown in Fig. 4 to be adapted to use in carrying out my invention and to have the advantages of being compact and reliable for the purpose. In Fig. 4 I have illustrated a structure corresponding to the board 90 and switches 94 and 98 of Fig. 1 in which 140 represents the armature stem or mechanically actuated stem of the switch. This stein carries for each switch a block or disk of insulating material 141, upon which is mounted an annular metal switch contact member 145 insulated from the stem 140. Mounted rigidly upon the switch board is a block of insulating material 144 which serves as a support and guide for one end of the stem'140, A pair of contact members 142 and 143 are mounted in recesses in the block 144, in position to be respectively simultaneously engaged by the. annular contact member 145 to close electrical contact from the member 142 to member 143 through the movable member 145. Each of the members 142 and 143 is preferably spring cushioned or yieldingly mounted in its recess in the block 144 by means of a spring 146. Each of the members 142 and 143 extends through the opposite side of the block 144 and is provided with nuts 147, or. similar means to conveniently attach an electrical conductor to'the members 142 and 1433. Switch structures of the type shown in Fig. 4 are adapted to be interchangeably substituted for the. other knife blade switches 43, 45, 59 and 74 shown in Fig. 1.

he apparatus herein shown and described is capable of considerable modification w thinthe scope of the claims without departing from the spirit of my invention.

What I claimis.

1. In combination with a normally open main alternating electrical circuit to be successively closed and opened, an auxiliary alternating current circuit having a plurality of circuit branches, a circuit closing and circuit opening member driven 1n synchronlsm with the current in said main circuit and adapted to close and open in ity of circuit branches, a circuit closing and circuit opening member driven in synchronism with the current in said main circuit and comprislng a portion havmg a plurality of main circuit closing sections adapted to be selectively employed to hold said main circuit closed for relatively different time periods, and comprising a second portion adapted to close and open in successive order gaps in, said auxiliary circuit, and means to independently close a gap in said auxiliary circuit to initiate a cycle of circuit closing and circuit opening movements.

3. In combination with a normally open main alternating electrical circuit to be successively closed and opened, an'auxiliary alternating current circuit, a rotary circuit closing and circuit opening member driven in synchronism with the current in said main circuit, an auxiliary circuit closing member movable into and outof the path of travel closin and circuit 0 enin member driven in synchronism with the current in said main c1rcu1t, an auxiliary circuit closing member movable into and out of the path of travel of said rotary circuit closing member and adapted to be actuated by said rotary circuit closing member to close and open said auxiliary circuit at prescribedperiods in the cycle of current flow of said auxiliary circuit, a main circuit closing member movable into and out of the path of travel of said rotary circuit closing member and adapted to be actuated by said rotary circuit closing member to close and open said main circuit at prescribed periods in the cycle of current flow of saidmain circuit, and means energized by said auxiliary circuit to shift said main circuit movable closing member into the path of travel of said rotary circuit closing member.

5. In combination with a plate holder containing a sensitive plate, an X-ray generator and a secondary circuit adapted to energize said X-ray generator, a normally open primary circuit adapted when closed to energize said X-ray generator andset up a train of X-rays from said generator to the sensitive plate, an auxiliary alternating circuit hav,-,

ing a manually closed gap and a synchronously closed gap, a rotary circuit closing member driven in synchronism with the current in said primary circuit, a primary circuit closing member movable into and out of the path of travel of said rotary circuit closingmember, and means energizedby said auxiliary circuit when closed to move said movable circuit closing member relative to said rotary circuit closing member.

6. In combination with a plate holder containing a sensitive plate, an X-ray generator and a secondary circuit adapted to energize'said X-ray generator, a normally open primary circuit adapted when closed to energize said X-ray generator and set upa train of X-rays from said generator to the sensi tlve plate, an auxiliary alternating circuit having a manually closed gap and a synchronously closed gap, a rotary circuit closing member driven is synchronism with the cur- I rent in said primary circuit, a primary circult closing member movable'into and out of the path of travel of said rotary circuit clos- 1 ing member, and means energized by said auxiliary circuit when closed to move said movable circuit closing member relative to said rotary circuit closing member, an auxiliary circuit branch normally open, means energized by closure of said auxiliary circuit branch to lock said auxiliary branch in closed position until positively opened, and an auxiliary branch closing member movable into and out of the path of travel of said rotary circuit closing member.

7. In combination with a plate holder containing a sensitive plate, an X-ray generator and a secondary circuit adapted to energize said X-ray generator, a normally open primary circuit adapted when closed to energize said X-ray generator and set up a train of X-rays from said generator to the sensitive plate, an auxiliary alternating circuit having a manually closed gap and a synchronously closed gap, a rotary circuit closing member driven in synchronism with the current in said primary circuit, having a plurality of engaging sections adapted respectively to close a gap in said primary circuit for relatively different fractions of the rotation of said circuit closing member, a primary circuit closing member movable into and out of the path of travel of said rotary circuit closing member, and means energized by said auxiliary circuit when closed to move said movable circuit closing member relative to said rotary circuit closing memher.

8. In combination with a normally open main alternating current circuit to be successively closed and opened, a main auxiliary alternating electrical circuit having a normally open positively closable switch and a second normally open intermittently synchronously closable switch and an auxiliary branch circuit normally open and adapted when closed to remain closed until. positively opened, a rotary circuit closing member driven in synchronism with the current in said main circuit, a circuit closing member adapted to be intermittently engaged by said rotary circuit closing member to intermittently and synchronously close said second switch in said main auxiliary circuit, a main circuit closing member movable into and out of engagement with rotary circuit closing member and adapted to c e said main circuit synchronously, an au 7, try circuit closing member adapted to close a switch in a second auxiliary branch circuit and movable into and out of engagement with said rotary circuit closing member and means energized by closure of said first auxiliary branch circuit and adapted to lock first auxiliary branch circuit in closed position to close and preventa repetition of the cycle of operation until said first auxiliary branch circuit is positively opened.

9. In combination with a normally open main alternating current circuit to be suc Nurse cessively closed and opened, a main auxiliary alternating electrical circuit having a normally open positively closablc switch, and a normally open intermittently synchronously closable switch, and an auxiliary branch circuit normally open and adapted when closed to remain closed until positively opened, a rotary circuit closing member driven in synchronisni with the current in said main and auxiliary circuits, an auxiliary circuit closing member adapted to be intermittently engaged by said rotary circuit closing member to intermittently and synchronously close said synchronously closable switch in said main auxiliary circuit, a. main circuit closing member movable into and out of engagement with said rotary circuit closing member and adapted to close said main circuit synchronously, and a second auxiliary circuit closing member adapted to close switch in a second auxiliary branch circuit and movable into and out of engagement with said rotary circuit closing member, and means energized by closure of said first auxiliary branch circuit and adapted to lock said first auxiliary oranch circuit in closed position to close and prevent a repetition of he cycle of operation until said first auxil ry branch circuit is positively opened.

10. In combination with a main alternating current circuit to be successively closed and opened, a main auxiliary alternating electrical circuit having a normally open positively closable switch, a normally open relay switch and a cooperating normally closed switch in a branch of said main auxiliary circuit and in said main auxiliary circuit, respectively, and a normally open intermittently synchronously closable switch in said main auxiliary circuit adapted to be synchronously opened, a second auxiliary branch circuit normally open and adapted when closed to remain closed until positive ly opened, a rotary circuit closing member driven in synchronism with the current in said main and auxiliary circuits, a main auxiliary circuit closing member adapted to be intermittently engaged by said rotary circuit closing member to intermittently and synchronously close said synchronously closable switch in said main auxiliary circuit, a main circuit closing member movable into and out of engagement with said rotary circuit closing member and adapted to close said main circuit synchronously, a second auxiliary circuit closing member adapted to open said normally closed cooperating switch in said main auxiliary circuit, and to close the normally open relay switch in said first auxiliary branch circuit and movable into and out of engagement with said rotary circuit closing member and means energized by closure of said second auxiliary branch cirlCTl signature.

WILBUR S. WERNER. 

